D-Link DIR-825 :: Internet Session TCP Timeout So Low - 120 Seconds?

I have a DIR-825 with 2.60VT firmware (rented from Videotron).

Even though the manual says the stateful firewall should have a timeout on connections of 240 seconds or 7800 seconds, all of my connections start at a mere 120 seconds. I'm having trouble with IMAP IDLE pushing e-mails because the connections timeout so quickly (before any stay alive can be sent). A connection to the e-mail server gets opened on 143 (Videotron) or 993 (encrypted - google, e.g.), and I see the connection on the Internet Sessions page, the timeout starts at 120. When it hits 0, the connection is no longer displayed (it is not renewed), and the IMAP IDLE ****s out because the server can't find the client (i.e. the connection has been closed). But it's not just on those ports or servers. ALL of my TCP sessions begin at a mere 120 seconds! Even for a home router, isn't this way too low?

confirm that their DIR-825, on the Internet Sessions page, shows initial timeout values of greater than 120 for a TCP connection? I would love to see a picture of that screen showing higher values. Does it start at 240? Do you ever see a connection start at a timeout of 7800?

I see no way of changing the timeout value. Is it possible to force connections on certain ports to begin at a higher timeout value?